1. Field of the Invention
The present invention relates to a liquid crystal display apparatus for use in liquid crystal television sets, monitors for car-navigation systems, OA apparatuses and mobile apparatuses.
2. Description of the Related Art
Liquid crystal displays are widely used as planar display apparatuses for computers, car-navigation systems and television receivers.
It is proposed that a liquid crystal display panel of OCB-mode be used in liquid crystal displays for television receivers that display mainly moving pictures. This is because the liquid crystal molecules of this panel exhibit good response. See, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-202491.
The liquid crystal display panel of OCB-mode comprises two substrates, a liquid crystal layer, and transparent electrodes. The liquid crystal layer is held between the substrates. Transparent electrodes are formed on the substrates, and are used as means for applying a voltage Before the power switch of the liquid crystal display having the panel is turned on, the liquid crystal molecules of the liquid crystal layer are aligned in a specific state called splay alignment. When the power switch is turned on, a relatively high voltage is applied between the transparent electrodes for a short time, changing the alignment of the liquid crystal molecules to so-called bend alignment. The use of the bend alignment characterizes the liquid crystal display panel of OCB-mode.
Most liquid crystal display panels of OCB-mode have an active-matrix substrate having a plurality of TFTs. Therefore, the panel can fast respond to input data, reducing the one-frame period to half the conventional one-frame period. For example, Jpn. Pat. Appln. KOKAI Publication No. 2000-214827 and Jpn. Pat. Appln. KOKAI Publication No. 2002-107695 disclose that a signal-display period and a black-display period are set in each one-frame period and the panel is driven, by utilizing the fast response of the panel.
In the liquid crystal display panel of OCB-mode, the liquid crystal molecules are prevented from undergoing inverse transition from bend alignment to splay alignment. That is, a high voltage is applied to the liquid crystal layer for a part of the one-frame period, thus driving the liquid crystal display panel of OCB-mode In the normally-white mode, the high voltage corresponds to a voltage that achieves black display. Therefore, the panel is driven in so-called black-insertion driving, thereby preventing the inverse transition to the splay alignment. Hence, the panel can acquire high transmittance.
However, the transmittance falls when the panel is driven in the black-insertion driving at low temperatures (0° C. or less).